Abstract
Abstract: :
Purpose: To evaluate a new animal model of hyperpressure-induced glaucoma and to ascertain its clinical relevance with structural and functional parameters. Methods: Intraocular hyperpressure were induced monocularly with an injection of methylcellulose (4%) in the anterior chamber of six healthy adult Göttingen minipigs. Measurements of the intraocular pressure (IOP) as well as fundus photography were taken at regular intervals, during the following 6 months, in order to monitor the condition thus created. Similarly, a complete electrophysiological evaluation of the retinal function, with the ERGs, was performed at three months (session 1) and six months (session 2) after the injection. At session 2, angiograms, taken with a Scanning Laser Ophthalmoscope (SLO) were also obtained in order to measure the arterio-venous filling time (AVFT), following which the animals were euthanized and the retina harvested for histological analysis of the irido-corneal angle (ICA) as well as inner retina layers (IRL). Results: For all animals the following clinical signs were observed in the treated eye: 1- significant mydriasis, 2- 20% increase in IOP, 3- significant reduction of the photopic ERG i-wave (presumed to be generated by the retinal ganglion cells and/or optic nerve) to almost non-recordable values, 4- near doubling of the AVFT 5- clear obstruction of the ICA and 5- significant loss of cells in the ganglion cells layer loss without alteration of the photoreceptor layer. Conclusion: The results summarised above clearly indicate that our model presents with several of the clinical signs reported in the human form of this disease and consequently could be used not only to study the pathophysiology of this disease but also, possibly, to investigate the beneficial effect of neuroprotective drug therapies.
Keywords: 316 animal model • 396 electroretinography: non-clinical • 415 ganglion cells